Degradation of three benzonitrile herbicides by AminobacterMSH1 versus soil microbial communities: pathways and kinetics

Abstract

The degradation pathway of the three benzonitriles is initially driven by similar enzymes, after which more specific enzymes are responsible for further degradation. Ioxynil and bromoxynil mineralization in soil is not dependent on previous benzonitrile exposure. The accumulation of dead-end metabolites, as seen for dichlobenil, is not a major problem.

Isotope Fractionation (δ13C, δ15N) in the Microbial Degradation of Bromoxynil by Aerobic and Anaerobic Soil Enrichment Cultures

“…This pathway was reported for Agrobacterium radiobacter , Variovorax sp. 11402, Rhodococcus erythropolis A4, Rhodococcus rhodochrous PA-34, Aminobacter MSH1, and Pseudomonas putida 13 XF . BrAM can be further hydrolyzed by amidase (route 2.1 in Scheme ) to produce BrAC, as shown for Rhodococcus erythropolis A4, Aminobacter MSH1, and Pseudomonas putida 13 XF. ,, (3) A nitrile hydroxylation pathway, leading to the formation of 2,6-dibromohydroquinone.…”

“…8 BrAM can be further hydrolyzed by amidase (route 2.1 in Scheme 1) to produce BrAC, as shown for Rhodococcus erythropolis A4, Aminobacter MSH1, and Pseudomonas putida 13 XF. 8,11,12 (3) A nitrile hydroxylation pathway, leading to the formation of 2,6-dibromohydroquinone. This pathway is less commonly reported.…”

Insights into the microbial degradation pathways of the ioxynil octanoate herbicide

“…By far, ioxynil degradation is the least studied benzonitrile herbicide and less data are available on ioxynil octanoate (Holtze et al, 2008). Ioxynil and ioxynil octanoate are selective post-emergent contact herbicides used to control broad-leaved weed growth in crops by the inhibition of photosynthesis (Frkova et al, 2014). The physical and chemical properties of ioxynil octanoate are shown in Table 1 in the Supplementary material.…”

Biodegradation of bromoxynil using the cascade enzymatic system nitrile hydratase/amidase from Microbacterium imperiale CBS 498-74. Comparison between free enzymes and resting cells

“…The latter depends on the local microbial communities whose composition is a result of complex physical and chemical factors. 4 Accordingly, control of the biodegradation process under bioreactor operation might be helpful. Recently, a biolm reactor able to degrade bromoxynil within a short time, 5 large scale bioreactors for the production of herbicide-degrading microorganisms, 6 and inoculated biolters for installation at local water facilities have been suggested.…”

“…Many microorganisms, belonging for example to Actinobacteria, 2,8,9 Agrobacterium radiobacter 8/4, 10 Aminobacter sp. MSH1, 4,6 Fusarium solani, Klebsiella pneumoniae ssp. ozonae, 11,12 Pseudomonas putida 13XF, Rhizobium radiobacter, Rhodococcus rhodochrous PA-34, Rhodococcus erythropolis A4, 8 Streptomyces felleus, Sphingobium chlorophenolicum ATCC 39723 and Variovorax sp.…”